Image forming apparatus

ABSTRACT

An image forming apparatus according to one embodiment of the present invention includes: an image generating unit configured to generate an image to be printed onto recording paper; a paper type specifying unit for a user to specify that a type of the recording paper is directly identified or that a type of the recording paper is automatically identified; a paper type identifier device having a recessed portion on an outer face of the image forming apparatus, the identifier device being operable to identify a type of the recording paper from a paper bundle made of a plurality of recording paper, inserted into the recessed portion by the user when automatically identifying a type of the recording paper is specified by the paper type specifying unit; and a printing unit configured to print the image generated by the image generating unit according to a type of the recording paper identified by the paper type identifier device.

CROSS-REFERENCE TO RELATED APPLICATION

The present invention is based on the benefit of priority of provisional application No. 60/982,109 filed on Oct. 23, 2007. The content of this provisional application is incorporated herein by reference in the present application.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to an image forming apparatus. In particular, the present invention relates to an image forming apparatus having a paper type identifier device.

(2) Description of the Related Art

Conventionally, types of media for printing color images have increased in image forming apparatuses such as multi-function type color copying apparatuses (MFP). Even if printing media are limited to paper, a variety of paper having different thicknesses are employed.

Types of such paper are, in general, discriminated by a basis weight (unit: g/m²) indicative of a weight per predetermined area, and for example, paper of groups of 64 to 105 g/m², 106 to 163 g/m², 164 to 209 g/m², 210 to 256 g/m², and 257 to 300 g/m² each are referred to as plain paper, thick paper 1, thick paper 2, thick paper 3, and thick paper 4. The basis weight of these pieces of paper depends on density and thickness of paper, and is proportional to the thickness if the density of paper is constant.

The basis weight is described in package of paper, and a user selects one of the groups of the described basis weight, thereby printing conditions according to the types of paper are automatically set.

However, many users are not aware of the basis weight described in the package of paper, and it becomes very difficult for general users to know the basis weight after paper has been taken out from the package.

Therefore, in recent years, an attempt has been made to cause a media sensor or the like installed in an apparatus to make selection of the paper described above, thereby eliminating user's inconvenience.

The media sensor identifies paper types by sensing characteristics of paper such as paper thickness or light transmission rate. It is preferable to separate paper into one piece in order to precisely sense the characteristics of paper. However, it is cumbersome for a user to separate only one piece of paper from a bundle of paper, and cause the media sensor to sense the characteristics of the paper. Therefore, before printing from a bundle of paper laminated in a cassette, the media sensor is installed in the course of a so called paper path after separation into one piece of paper. In this case, paper types cannot be discriminated after one piece of paper has reached the media sensor, in other words, until paper has been separated into one piece immediately before printing.

In general, in apparatus for forming and printing images, it is preferable to adjust image forming conditions according to the characteristics of paper types, and it is preferable that paper types be discriminated until image forming has been started. Hence, in the apparatus for forming and printing the images, in general, images are formed before one piece of paper is separated from a bundle of paper. Therefore, even if paper types are discriminated at this stage, it is difficult to replace one type of paper being in a printing state with another type of paper. Even if such replacement can be made, it is necessary to cancel running of paper being in a printing state, and bring another piece of paper in a printing state, lowering printing performance.

It has been thought to sense characteristics of paper in a state in which bundles of paper are laminated in a cassette. For example, in Japanese Patent Application Laid-open No. 2005-104723, a CCD sensor is mounted at a position opposite to a side end face of a bundle of sheets set at a sheet supply tray (cassette) of an image forming apparatus, and the side end face of the bundle of sheets is picked up as an image by this CCD sensor. In this publication, there is disclosed a sheet supply apparatus for detecting thickness or the like of sheets from the picked up image.

However, because shading caused by paper (sheet) itself and a paper gap is utilized in this method, the contrast of shading is unlikely to occur, and it is difficult to precisely measure the thickness or the like of paper.

The above publication describes that a light is irradiated obliquely upward or obliquely downward of the side end face of the bundle of sheets in order to increase a difference in contrast of shading. However, if the side end position of the bundle of sheets is precisely aligned, the difference in contrast is unlikely to occur, and on the other hand, if the side end position of the bundle of sheets is nor precisely aligned, variation occurs in the length of a shade, and it is difficult to precisely sense the thickness or the like of sheet. In addition, while, in the publication, there is disclosed that perpendicular movement of the bundle of sheets is utilized and that air is blown from the side face of the bundle of sheets, it is still difficult to precisely measure the thickness or the like of sheets.

Further, in the apparatus described in the publication, another cassette is provided for each type of paper. Thus, for example, in the case where four types of paper are used, four stages of cassettes are required, four sets of types of paper sensing means are required, and the cost becomes four times as high as usual.

BRIEF SUMMARY OF THE INVENTION

The present invention has been made in view of the conventional problems described above. The present invention provides an image forming apparatus and an image forming method of an image forming apparatus, which are capable of precisely discriminating types of paper without separating one piece of paper from a bundle of paper, with no need for types of paper sensing means on each cassette even if plural types of paper are present, and without degrading printing performance.

According to one aspect of the image forming apparatus of the present invention, there can be provided: an image generating unit configured to generate an image to be printed onto recording paper; a paper type specifying unit for a user to specify that a type of the recording paper is directly identified or that a type of the recording paper is automatically identified; a paper type identifier device having a recessed portion on an outer face of the image forming apparatus, the identifier device being operable to identify a type of the recording paper from a paper bundle made of a plurality of recording paper inserted into the recessed portion by the user when automatically identifying a type of the recording paper is specified by the paper type specifying unit; and a printing unit configured to print on the recording paper the image generated by the image generating unit according to a type of the recording paper identified by the paper type identifier device.

According to one aspect of the present invention, light is irradiated to one face of a bundle of paper made of a plurality of recording paper (hereinafter, referred to as paper); and the leak light is sensed from a side face of the bundle of paper, thereby sensing the characteristics such as thickness of paper and identifying types of paper.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a multi-function type color copying apparatus according to one embodiment of the present invention;

FIG. 2 is a cross-sectional view showing a structure of a paper type identifier device in one embodiment of the present invention;

FIG. 3 is a block diagram depicting an electrical configuration of the paper type identifier device shown in FIG. 2;

FIG. 4 is a block diagram depicting an entire configuration of the copying apparatus according to one embodiment shown in FIG. 1;

FIG. 5 is a plan view of an operating panel 102 in the embodiment;

FIG. 6 is a view showing a display screen of a touch panel display 300 of the operating panel 102 shown in FIG. 5;

FIG. 7 is a view showing a flow chart for explaining an operation of a paper type identifier device 106;

FIG. 8 is a view showing a display screen of a touch panel display 300 when types of paper are reset;

FIG. 9 is a view showing a display screen of the touch panel display 300 when a type of paper is sensed;

FIG. 10 shows a state in which a bundle of paper is inserted in a recessed portion of the paper type identifier device 106;

FIG. 11 is a view showing arrangement of two-dimensional CCD light receiving elements as one example of an image sensor of the paper type identifier device;

FIG. 12 is a view showing an example of a leak light curve I1 and an integral leak light curve I2;

FIG. 13 is a view showing a paper bundle thickness direction (X-axis direction) and a direction perpendicular thereto (Y-axis direction);

FIG. 14 is a block diagram depicting an electrical configuration of the touch panel display 300;

FIG. 15 is a block diagram depicting an entire electrical configuration of the embodiment; and

FIG. 16 is a view showing an example of optically integrating leak light in a direction substantially perpendicular to the paper bundle thickness direction.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of an image forming apparatus according to the present invention will be described with reference to the accompanying drawings. In the following, a description will be given assuming that the image forming apparatus of the embodiment is a multi-function type color copying apparatus.

FIG. 1 is a perspective view showing one example of an appearance of the multi-function type copying apparatus according to the embodiment of the present embodiment.

At the upper part f apparatus main body 100, an Auto Document Feeder (ADF) 101, which is compatible with a document cover and which automatically feed sheets of a document on one by one basis, is openably provided. At the frontal upper part of the apparatus main body 100, an operating panel 102 is provided and includes a variety of operating keys for indicating copy conditions and start of copying and a variety of display devices or the like.

At the lower part of the operating panel 102 on the front face of the apparatus main body 100, a grip 104 is provided to allow opening of the inside of the main body when paper jamming or the like occurs. On the front face of the apparatus main body 100, a paper type identifier device 106, which will be described later in detail, is provided at the lower corner of the operating panel 102. Therefore, it is easy to use the paper type identifier device 106 while verifying the display of the operating panel 102.

Paper feed cassettes 102, 153, and 154 are removably provided at the lower part of the apparatus main body 100. In each of these paper feed cassettes 152, 153, and 154, paper of the same size is housed in a lateral direction or in a perpendicular direction. The paper is selected and fed when printing is carried out.

At the right side part of the apparatus main body 100, an automatic double-side unit 155 for carrying out a double-side copy and a manual tray 156 that can be folded when it is not used, the tray being adapted to manually feed paper, are removably provided. At the opposite side of the apparatus main body 100, a paper discharge tray 162 for receiving printed paper is provided.

At the rear face of the apparatus main body 100, terminals such as a parallel port, a serial port, and SCSI are provided, although not shown. The parallel port makes connection between the apparatus and an external device such as a personal computer (PC) when the apparatus is operated as a printer.

The serial port makes connection between the apparatus and an external device such as a PC, in order to read out internal management information of the apparatus and to set functions of the apparatus.

The SCSI makes command or data communication between this apparatus and an external controller that operates as a master.

Now, a structure and a control system of the paper type identifier device 106 will be described with reference to FIG. 2 and FIG. 3. FIG. 2 is a unital view showing a basic structure of the paper type identifier device 106 and a state in which a bundle of paper 102 is inserted into the device.

The paper type identifier device 106, as shown in FIG. 1, is provided at the corner of the apparatus main body 100, and is structured to have a recessed portion 121 in the lateral direction, as shown in FIG. 2. The paper type identifier device 106 includes: alight source 122 installed upwardly of the recessed portion 121 so as to irradiate light downwardly; and an image sensor 123 provided at the bottom of the recessed portion 121 so as to be proximal to an end of a bundle of paper 120 inserted into the recessed portion 121.

FIG. 3 shows an example of an electric circuit configuration in the case where paper thickness is measured, and a type of paper is sensed in the paper type identifier device 106.

This paper type identifier device 106 includes: a paper bundle insertion sensing unit 101 for sensing that a bundle of paper 120 has been inserted into the recessed portion 121; a paper type identification control unit 133 for receiving an insertion sensing signal of the bundle of paper 120, and instructing a light irradiating unit 132 to irradiate light to the bundle of paper; a leak light detecting unit 134 for detecting leak light from an end of the bundle of paper, and converting the detected light intensity into an electrical signal; an integrating unit 135 for integrating this electrical signal in the direction along the end of paper; an inter-peak distance detecting unit 136 for detecting a distance between peaks of the integrated leak light signal; and a paper type identifying unit 137 for sensing paper thickness from the detected inter-peak distance and identifying types of paper. The paper type identification control unit 133 controls the paper bundle insertion sensing unit 131, the light irradiating unit 132, the leak light detecting unit 134, the integrating unit 135, the inter-peak distance detecting unit 136, and the paper type identifying unit 137.

Information on types of paper identified by the paper type identifying unit 137 of this paper type identifier device 106 is fed back to each unit in the image forming process, thereby more proper printing can be carried out. In this case, as shown in FIG. 3, an image forming unit 138 is connected to the paper type identifying unit 106. This image forming unit 138 includes: a latent image generating unit 139 for scanning an image to be copied, for example, thereby generating an optical latent image; a developing unit 140 for developing, by apparatus such as a toner, the latent image generated by the latent image generating unit 140; a transfer unit 141 for transferring onto paper a visible image developed by the developing unit 140; and a fixing unit 142 for fixing the transferred image.

When types of paper are identified at the paper type identifying unit 137, the paper type information is transmitted to the image forming unit 138. Then, according to the types of paper, printing conditions, for example, a transfer bias voltage of the transfer unit 141, a voltage applied at the time of development at the developing unit 140, and a fixing temperature at the fixing unit 142 can be changed. In this way, by automatically changing the printing conditions according to types of paper, a proper printing image can always be obtained.

A bundle of paper 120 is made up of a plurality of recording paper, light is irradiated from a light source in the paper bundle thickness direction, and light leaking from the end face of the bundle of paper to the outside between sheets of paper is sensed.

At the paper bundle insertion sensing unit 131, sensing light sources, for example, a light emitting diode 128 and a light receiving device 129 (paper bundle insertion sensing sensor) are provided on the upper and lower close to the bottom of the recessed portion 121. This sensing unit senses that the light from the light emitting diode 128 is interrupted by the inserted bundle of paper. Alight source 122 is included in the light irradiating unit 132. The image sensor 123 is included in the leak light detecting unit 134. An operation carried out when the bundle of paper 120 is inserted into the recessed portion 121 of this paper type sensor device 106 will be described later.

FIG. 4 is a block diagram depicting an exemplary configuration of a control system in a multi-function type color copying apparatus according to the embodiment.

The apparatus includes: a system CPU 200; a flash ROM 201 for storing programs or fixed data; a font ROM 202 for converting text data into font data; and a nonvolatile RAM (NVRAM) 203 and a DRAM 204 for working and data storing.

The system CPU 200 controls the entire apparatus. More specifically, this CPU controls functions according to a command signal from the operating panel 102 by users and signal input from a communication line, and an input signal from a variety of external interfaces.

A scanner interface (SIF) 205 receives image data from a scanner unit 205S. An image processor circuit 206 carries out image editing processes such as an image enhancement process according to recording media, an expansion and reduction process, a pixel decimating process, a process for whitening a specified area by marker detection.

A printer interface (PIF) 207 feeds image data to a printer unit 207P. A page memory 208 stores, on a page by page basis, image data queued to be output, the image data having been processed by the image processor circuit 206. This memory functions as a page buffer for temporarily storing image data and performs CODEC for carrying out compression and decompression.

A control signal is exchanged at a high speed by a system bus 211 between the system CPU 200 and each of the devices including the paper type identifier device 106. On the other hand, devices associated with image signal processing are connected via an image bus 212.

The image bus 212 is uniquely provided when the apparatus operates as a copying machine and the image bus 212 performs the following operations in parallel. In order to guarantee a real time operation of the copying machine, the scanner interface 205 receives image data input from the scanner unit 205S; the image processor circuit 206 carries out a variety of editing processes such as an image enhancement process and an expansion and reduction process; and the printer interface 207 carries out an operation of carrying out printout to the printer unit 207P. Hereinafter, this processing operation is referred to as basic copying.

Among the boards connected to the image bus 212, a processing board that is unnecessary for desired operation is in a passed state.

A mass capacity storage device, for example, a hard disk driving circuit (HDD) 209 stores image data provided from an external device and image data or the like associated with printing a plurality of copies obtained at the scanner unit 205S.

A printer network controller (PRNC) 210 includes an interface with the printer unit 207P, for controlling an image forming function at the time of a copying operation or a printer operation. At the same time, this controller is LAN-connected via a built-in device such as a network interface card, and carries out protocol control and data transfer/compression/decompression control for receiving print data via a LAN from a device such as an external personal computer, buffering data, and transferring data to the printer unit 207P.

FIG. 5 is a view showing an exemplary configuration of an operating panel 102. On the operating panel 102, a touch panel display 300 is provided at the left side thereof; and a start key 301, a stop key 302, a reset key 303, a ten key 304 for setting numbers, and a function mode selection key 305, which is capable of selecting functional modes such as copy and facsimile modes are provided at the right side thereof. A print mode is used when printing is carried out while an external device such as a personal computer is connected.

The ten key 304 is disposed in the same manner as ten key arrangement such as a button type telephone set so that it can be shared in copying, facsimile processing, and printing.

The touch panel display 300 displays a touch panel guidance screen as shown in FIG. 6, for example. A total of five modes such as a basic mode, an image adjust mode, an advanced mode, a store mode, and a confirm mode are available. One of these modes can be selected by touching the tab displayed.

In the basic mode, as shown in FIG. 6, a main body side face icon 401 is displayed, the icon indicating a side face of the apparatus main body at the left side, and a color/monochrome icon 402 is indicated at the right side such that one of the color, black, and auto printing images is selected. At the further right side of these icons, there are displayed: a copy magnification icon 403; a single-side/double-side icon 404; a sort icon 405; an image type icon 406; a paper type icon 407 indicating types of recording paper; and a contrast icon 408 that illustrates contrasts and that is capable of selecting one of the illustrated contrasts under these icons.

By touching the copy magnification icon 403, the single-side/double-side icon 404, the sort icon 405, or the image type icon 406, a selection display screen is displayed so that one of optional functions in each icon can be selected. On the selection display screen, a user selects one of the functions by touching it with finger, thereby the selected option is displayed in the icon by turning to the display screen shown in FIG. 6.

For example, the user touches the single-side/double-side icon 403, thereby selecting whether a document to be printed is single-sided or double-sided. For example, if it is selected that the document printed on double sides is printed on a single side, the single-side/double-side icon 404 shown in FIG. 6 is displayed as “double-side→single-side”.

In an initial state, printing is made presuming that recording paper is plain paper, and the paper type icon 407 is displayed as plain paper. Now, an operation of the paper type identifier device 106 when a user inserts a bundle of paper 120 into a recessed portion 121 will be described according to FIG. 7.

In step S101, a touch panel guidance screen as shown in FIG. 6 is displayed as a first guide screen. In step S102, it is sensed whether or not a paper type is changed according to whether or not a user touches a paper type icon 407.

When the paper type icon 407 is touched, as shown in FIG. 8 in step S103, for example, a paper type sensing guidance screen on which icons of paper types are arranged is displayed as a second guide screen (step S103).

In this case, icons 421, 422, 423, 424, and 425 of plain paper, thick paper 1, thick paper 2, thick paper 3, and thick paper 4 and an icon 426 displayed as paper type sensing are displayed. A message “select a paper type” is displayed upwardly of each of these icons, and a message “touch for automatic paper type sensing” is displayed at the side of the paper type sensing icon 426.

In the case where a user knows a paper type by basis weight or the like, the icons 421 to 425 are directly touched, and a paper type can be selected. After that, a set icon 428 displayed at the lower right of a display screen is touched, and the paper type can be set.

In step S104, it is sensed whether or not the user touches an icon other than the paper type sensing icon 426. After any of these icons has been touched, in the case where the set icon 428 is touched, the procedure proceeds to step S106 in which the paper type is determined, and the procedure returns to the touch panel guidance screen shown in FIG. 6.

On the other hand, in the case where the user does not know a paper type, the paper type sensing icon 426 is touched. This is sensed in step S107, and the screen of FIG. 9 is displayed. On the screen shown in FIG. 9, a message “Insert a unpacked paper bundle into a lower left paper bundle insertion opening” is displayed together with the left-oriented arrow. As shown in FIG. 1, the type paper identifier device 106 is situated at the lower left viewed from the user, and the user can easily find the paper bundle insertion opening (recessed portion 121) of the paper type identifier device 106. The paper bundle to be inserted into the recessed portion 121 is taken out from a package, and if the entirety is distorted once, recording paper is spaced, and a space is slightly provided. Thus, when the paper thickness is measured, such a space is preferable.

When the user inserted a paper bundle 120 into the recessed portion 121, as shown in FIG. 10, a paper bundle insertion sensing unit 131 shown in FIG. 3 senses a tip end of the paper bundle 120 in step S108. A paper type identification control unit 133 feeds a light irradiation start signal to a light irradiating unit 132, and in step S109, a light source 122 downwardly irradiates light whose cross unit is circular to a top face of the paper bundle 120. It is desirable that a distance between the light source 122 and the paper bundle 120 is a distance to an extent such that they come into slight contact with each other. This is because leak light is strong when the light irradiated from the light source enters the paper bundle 120 to the local maximum level; paper thickness or the like can easily measured using an electrical signal by the strong leak light; and it is possible to prevent that the light irradiated from the light source directly enters an image sensor and adversely affects the leak light. In order to cause the light source to be proximal to the paper bundle when the leak light is sensed, in general, the light source is spaced, a switch is installed near an inlet of the recessed portion, or alternatively, the light emitting diode 128 and the light receiving device are provided, thereby insertion of the paper bundle is sensed and the light source is brought into slight contact with the surface of paper of the paper bundle by a mechanism in which a motor is used as a drive source. Then, when detection of the leak light terminates, the light source may be spaced from the paper bundle again. By doing so, paper characteristics can be precisely sensed by the leak light, and moreover, a paper type identifier device with its good operability can be obtained.

However, when a light interrupt plate is provided so that irradiation light to the paper bundle does not enter the image sensor, it is possible for the light source and the paper bundle to be spaced from each other to some extent.

The paper bundles 120 are stacked in sequentially order of a top (first) paper 124 a, a second sheet of paper 124 b, and a third sheet of paper 124 c. A space 125 a is provided between the first sheet of paper 124 a and the second sheet of paper 124 b; a gap 125 b is provided between the second sheet of paper 124 b and the third sheet of paper 124 c; and a gap 125 c is provided between the third sheet of paper 124 c and a fourth sheet of paper 124 d.

Because paper is an aggregate of fiber, although part of the irradiation light is reflected on the surface of paper, the other light transmits the paper. In other words, although part of the irradiation light 126 of the light source 122 is scattered and reflected from the first sheet of paper 124 a, the remaining light disperses and propagates the paper 124 a, part of which transmits the paper and reaches the gap 125 a. Although part of the light having reached this gap 125 a is reflected by the second sheet of paper 124 b, and propagates the inside of the gap 125 a in the lateral direction, the remaining light disperses and propagates the inside of the second sheet of paper 124 b, part of which reaches the gap 125 b. Although part of the light having reached the gap 125 b is reflected by the third sheet of paper 124 c, and propagates the inside of the gap 125 b in the lateral direction, the remaining light disperses and propagates the inside of the third sheet of paper 124 c, part of which reaches the gap 125 c. In the following, similarly, the irradiation light 126 sequentially passes from the first sheet of paper 124 a of the paper bundle 120 through each sheet of paper while the light attenuates, and part of the light leaks from a gap between these sheets of paper. The leak light 127 is received by the image sensor 123 of the leak light detecting unit 124 (step S110).

As the image sensor 123, as shown in FIG. 11, for example, there can be employed a two-dimensional sensor in which CCD light receiving elements 129 are arranged in a two-dimensional manner in the X-axis direction and in the Y-axis direction. In FIG. 1, although the CCD light receiving elements 129 are shown in an enlarged manner, in actuality, a plenty of light receiving elements are arranged at a high density, and thus, a two-dimensional sensor is produced. The light having leaked from an end of a paper bundle to the outside, i.e., the leak light is converted from an optical signal to an electrical signal at a leak light sensing unit.

FIG. 12 shows an example of measuring the light received by the image sensor 123. In the figure, the horizontal axis (X axis) indicates the X direction shown in FIG. 13, i.e., the position in the direction from the first to second sheets of paper, and the perpendicular axis indicates light intensity at that position.

An electrical signal corresponding to the light intensity at a given position in the X-axis direction appears as a light curve I1 indicated by the dotted line. This optical signal is integrated in the lateral direction, in other words, in a direction substantially perpendicular to the light irradiation direction on an end face (the direction indicated by Y in FIG. 13) in an integrating unit 135 of FIG. 3. Then, an electrical signal having light intensity appears as an integral leak light curve I2 indicated by the solid line in FIG. 12. A difference between a local maximum value and a local minimum value in light intensity of this integral leak light curve I2 becomes greater than that between a local maximum value and a local minimum value in light intensity of the leak light curve I1 (step S111). The “substantially perpendicular direction” used here denotes that the direction may not always be perpendicular if the leak light in the Y direction is obtained.

A gap between a position of a given local maximum value and a position of the adjacent local maximum value in the leak light curve I1 and the integral leak light curve I2, or alternatively, a gap between the position of a given local minimum value and a position of the adjacent local minimum value is referred to as an inter-peak distance.

In step S112, an inter-peak distance detecting unit 136 measures an inter-peak distance of a maximum value, for example, of light intensity. In FIG. 12, an inter-peak distance P2 corresponds to thickness of the second sheet of paper.

Advantageously, by integrating an electrical signal of the leak light obtained from the side face of a paper bundle in a direction substantially perpendicular to the light irradiating direction; a distance between the peak values increases; an inter-paper distance can be easily measured, and paper thickness can be easily and precisely measured. However, in the present invention, the leak light does not always need to be integrated in the lateral direction.

In step S113, a paper type identifying unit 137 shown in FIG. 3 identifies a paper type from the inter-peak direction measured at the inter-peak distance detecting unit 136.

As described above, a paper type is automatically sensed by the paper type identifier device 106, and the automatically sensed paper type is displayed on the paper type icon 407 of the touch panel guidance screen shown in FIG. 6.

A main body side face icon 401 displays the entire status of an apparatus main body, for example, and, is employed to indicate a paper cassette at which paper is set or a fault location.

In addition, at the upper left part of this touch panel display 300, for example, there are displayed a currently set expansion and reduction magnifications, the number of copies, and size of paper.

For example, in the case where five copies are made, a function mode selection key 305 is changed to “copy”, and a one-side/double-side icon 404 is touched, thereby selecting a desired process such as a double-side copy, and a key of “5” of a ten key 304 is pressed.

Then, the selected number is displayed in an upper right area on the touch panel display 300. After the user has confirmed this displayed number, a document is set, and a start key 301 is pressed, thereby a copy operation is started, and five copies are made.

FIG. 14 is a block diagram depicting an electrical configuration of the touch panel display 300 described above.

The touch panel display 300 is configured while a touch panel 520 is superimposed on a liquid crystal display 521. On the touch panel 520, a transparent resistor is uniformly coated on a transparent substrate, and transparent electrodes are arranged in parallel to each other in a predetermined distance in the X and Y directions.

Under the control of a touch panel control unit 522, voltages are sequentially applied in a predetermined direction on each of the transparent electrodes in the X and Y directions of the touch panel 520. An operation of indicating a position relative to the touch panel 520 is carried out with the use of a dedicated electrically conductive pen or a user's finger.

The touch panel control unit 522 monitors a resistance value between electrodes in each of the X and Y directions, and detects a position at which a resistance value has been locally reduced, by the electrically conductive pen or finger indication, through computation from the resistance value between the electrodes.

In addition, to the liquid crystal display 521, a display control unit 522 for driving the display is connected, and a video RAM (VRAM) 524 for storing display data in units of display pixels is connected to the display control unit 522.

In the touch panel display 300 made of the above configuration, the position data obtained by a touch panel control unit 523 is read by a system CPU 200 (refer to FIG. 4) in a main control unit, and a processing operation corresponding to the position data is executed by the system CPU 200. For example, in the case where a manual input is made, this touch panel display 300 can be used for a variety of usage such that data existing on the video RAM 524 corresponding to the position indicated on the touch panel 520 is inverted from an inactive state to an active state or operating parameters are input by a selection from among the keyboard display or a variety of set buttons displayed on the liquid crystal display 521.

FIG. 15 is a block diagram depicting a functional configuration of a control unit in a multi-function type color copying apparatus according to the present embodiment. This control unit includes a control unit or the like, for various constituent elements such as the system CPU 200 operable to execute programs or fixed data stored in a flash memory 201 and a touch panel control unit 523. This control unit can be functionally shown in FIG. 15.

A scanner control unit 530 includes a scanner control ASIC, scanner control firmware operable to make scanner drive control or ADF control at the time of image input, and a preprocessing image processing unit operable to carry out shading correction or the like. This control unit is mounted on the scanner unit 205S shown in FIG. 4.

A printer control unit 531 includes a printer control ASIC, an output side image processing ASIC, printer operation control firmware operable to carry out printer control at the time of printing or paper transportation control or the like, and printer side image processing firmware mounted on a printer unit 52.

In addition, the printer control unit 531 includes an interface with a printer driver of a personal computer or the like, and carries out command communication of a control command or a status and print data communication control. In addition, this printer control unit carries out execution control of both of printout of the image data input from the scanner unit 205S and image data output transmitted from a printer driver.

The scanner control unit 530 and the printer control unit 531 each includes a control CPU, and achieves control at a high speed. These control units carry out command-status communication with the system CPU 200 shown in FIG. 4, controls synchronizing operations of displaying, scanning, and printing, and achieves a copy operation and a printout operation of the entire apparatus.

An input/output operation control unit 532 includes an image processing unit and an interface between the scanner control unit 530 and the printer control unit 531. This control unit carries out drive timing control of the scanner unit 205S and a printer unit 207P by triggering an operation start command or the like received from a whole operation control unit 533. At the same time, this control unit calculates image processing parameters, provides setting for the image processing circuit 206, and control a copy function.

Timing control denotes, for example, specifying an ADF drive timing, a scanner drive timing, a process for qualifying an image expanded in memory, a printing start timing, or a next document input start timing. In addition, a secure/release command relevant to a printer resource received from the display control unit 534 or the like is also notified to the printer control unit 531.

The display control unit 534 is made up of display control software for controlling the operating panel 102 of this apparatus described above with reference to FIG. 5 and FIG. 6. Here, operational information on the operating panel 102 is transmitted to the whole operation control unit 533 and a variety of state changes having occurred with apparatus are received as information by a machine state management unit 535, and the received changes are included in a display. In addition, information relevant to a result and a progress of processing such as a copy result, the number of copies in copy, or size information is received by the whole operation control unit 533, and the received information is included in a display. This including method denotes illumination of LED on the operating panel 102 or message display on the liquid crystal display 521.

The whole operation control unit 533 further always monitors an operation state of entire apparatus and carries out exclusive control of resources shared by a plurality of functions such as the scanner unit 205S and the printer unit 207P, priority operation of copy or print data printing, and a screen unit change operation or the like. For example, in the case where a copy screen is in operation or in the case where copying is preferentially executable, printing of print data is disabled for a predetermined period of time. In turn, if printing of print data starts, the screen is changed to “printing”, and execution of copying is restricted. In addition, time control of timer monitoring or the like is carried out, and, according to a state, a menu change control or the like is properly carried out for the display control unit 534.

The machine state management unit 535 monitors a state of a machine notified from the scanner control unit 530 and the printer control unit 531. Specifically, this management unit monitors information such as paper jamming, jamming release, and front cover opening or closing, and notifies the fact to the whole operation control unit 533 or the display control unit 534, thereby including an error state in a display or including the error state in judgment of whether or not to execute a copy operation.

In addition, a machine recovery operation at the end of a job is managed at the time of error recovery by an instruction from the whole operation control unit 533. The recovery operation in this case denotes a preparation operation for making next copy such as initialization of an indicator position of the scanner unit 205S or a warming up operation of a heat roller unit.

A data transfer control unit 536 has a function of transferring data between external devices. This data transfer control unit 536 includes a printer network controller (PRNC) 210 shown in FIG. 4. This control unit also include a scanner or a printer connected via a LAN, or alternatively, software for controlling control signal and image data communication with a digital copying machine. The printer network control 210 is made up of a network interface card (NIC) and a buffer memory or the like.

In this multi-function type copy copying apparatus, on the operating panel 102 shown in FIG. 5, a user selects a function by pressing any key of the function mode selection keys 305. The paper type icon 407 is provided as described above.

A user press a copy key and inputs the number of copies by the ten key 304 when the user desires to make a copy, for example. At this time, the user looks settings displayed on the first guide screen displayed on the touch panel display 300. If the user desires to change these settings, the corresponding icon is touched with a finger and the setting is changed. In the settings in which three or more selections exist, the selections are displayed on the second guide screen that appears next. For example, when the copy magnification icon 403 is touched, a current magnification, an up key, and a down key are displayed on the second guide screen. The up key is touched, allowing the magnification to be increased. The down key is touched, allowing the magnification to be reduced. After the selecting has terminated, a “return” icon (not shown) is touched, and the first guide screen is restored. If the settings are acceptable on the first guide screen displayed on the touch panel display 300, the star key 301 shown in FIG. 5 is pressed.

The information specified on the operating panel 102 including the touch panel display 300 is sent to the whole operation control unit 533 via the display control unit 534 shown in FIG. 15, and the entire control is carried out.

In the case of copying, the information specified or automatically identified by the paper type icon 407 described above and the information on the number of copies are sent from the display control unit 534 to the input/output operation control unit via the whole operation control unit 533. Further, the above items of information are sent to the printer control unit 531, and the operation is controlled so that proper printing is carried out according to the paper type.

When the function mode selection key 305 has selected each of the LAN, PRN, and FAX modes, the function mode selection signal is transmitted from the display control unit 534 to the whole operation control unit 533, and is transmitted to the machine state management unit 535. This multi-function type color copying apparatus is in a state suitable for the selected mode.

According to the embodiment, there can be provided a multi-function type color copying apparatus in which, even if a user does not know a paper type of recording paper at the time of printing, and no paper type is input, the paper type can be identified automatically and easily precisely, and the entire printing time is never extended.

In the multi-function type color copying apparatus of the embodiment, the paper type identifier device 106 is provided at the lower left of the operating panel 102. When a paper type is automatically identified, a sentence for guiding insertion of a paper bundle is displayed on the touch panel display 300 included in the operating panel 102. Therefore, a user can easily inserts a bundle of paper into an insertion opening of the paper type identifier device 106, and automatically identify the paper type.

However, in the case where the user can find the paper type identifier device immediately in the present invention, it is not always necessary to display on the touch panel display a message prompting insertion of a bundle of paper into the paper type identifier device. The present invention can also be applied to an image forming apparatus with no operating panel having a touch panel display.

The paper type identifier device of the embodiment is constructed so that light is irradiated downwardly to a bundle of paper. However, the present invention does not always need to irradiate light downwardly to the bundle of paper. For example, light is irradiated upwardly from the bundle of paper, thereby the leak light may be detected at an end part of the bundle of paper. When the paper bundle is inserted longitudinally without being flatly inserted into the insertion opening, light is irradiated to the paper bundle from the lateral direction, it is possible to detect the leak like at the end part thereof. In short, in the present invention, light is irradiated substantially vertically onto a plane of the paper bundle made of a plurality of paper sheets, so that the light leaking from the end part of the paper bundle between recording paper may be detected in the thickness direction of the paper bundle. The end part of the paper bundle in this case does not denote a portion of a short edge of recording paper, and the leak light from a portion of the long edge may be detected.

In the embodiment described above, the image sensor is made up of two-dimensional CCD light receiving elements. However, the present invention does not always need such two-dimensional light receiving elements. A one-dimensional optical sensor provided near the end face of the paper bundle can be employed in the thickness direction of the paper bundle made of a plurality of paper sheets.

While, in the embodiment, a signal of which the leak light of irradiation light from the paper bundle is electrically integrated in the Y direction of FIG. 13 is obtained at the integrating unit 135 of FIG. 3, and the inter-peak distance is obtained from this signal. However, the leak light signal can also be optically integrated. FIG. 16 is a top view showing an apparatus of this embodiment. In the embodiment, a cylindrical lens 160 is arranged in front of the image sensor 123. Although the leak light of light 161 irradiated to the paper bundle 120 goes out from this end part, this leak light enters the cylindrical lens 160, and the leak light in the Y direction is collected by the image sensor 123. Therefore, according to the embodiment, there is attained an advantageous effect that the leak light can be collected in a comparatively wide range in the Y direction, and a leak light signal with a large difference between the maximum and minimum peak values can be obtained. A lens having a refractive index distribution can also be employed instead of the cylindrical lens. In short, an optical lens maybe provided for focusing the leak light in a direction that is substantially perpendicular to the thickness direction of the paper bundle.

The foregoing embodiment has described a case in which paper thickness is sensed by the leak light from the end part of the paper bundle, and a paper type is identified. However, the distribution of the leak light shown in FIG. 12 has characteristics depending on paper density or the like as well as paper thickness. Therefore, for example, it is also possible to sense the paper density or the like from the distribution of the leak light, calculate a value equivalent to a basis weight, and identify the paper type.

When the following configuration is provided in the present invention, a paper type identifier device with further good operability can be provided. In order to associate paper identifying a type of paper with a cassette for housing the paper, a cassette for housing the paper bundle is drawn out before making an operation of identifying a type of paper as described above. After the drawn out cassette has been sensed, when the paper bundle is identified, a copying apparatus according to one example of the present invention can store the identified paper bundle to be associated with the cassette.

In addition, a paper type identifier device is installed in the vicinity of the cassette, and at a detection opening thereof, a guide tapered from the opening side toward the back is provided. With such a structure, there is an advantageous effect that a bundle of paper can be easily inserted.

In the embodiment described above, there is attained an advantageous effect that, even with a copying apparatus having a plurality of cassettes, paper types mounted on all of the cassettes can be identified merely by providing one paper type identifier device.

While the foregoing embodiment has described a case in which the present invention is applied to a multi-function type color copying apparatus, the present invention can also apply another image forming apparatus including an image generating unit for generating an image to be printed onto recording paper and specifying a paper type to be printed, such as a general copying machine, a printer, or a facsimile.

Obviously, many, modifications and variations of this invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims, this invention may be practiced otherwise than as specification. 

1. An image forming apparatus comprising: an image generating unit configured to generate an image to be printed onto recording paper; a paper type specifying unit for a user to specify that a type of the recording paper is directly identified or that a type of the recording paper is automatically identified; a paper type identifier device having a recessed portion on an outer face of the image forming apparatus, the identifier device being operable to identify a type of the recording paper from a paper bundle made of a plurality of recording paper inserted into the recessed portion by the user when automatically identifying a type of the recording paper is specified by the paper type specifying unit; and a printing unit configured to print on the recording paper the image generated by the image generating unit according to a type of the recording paper identified by the paper type identifier device.
 2. The image forming apparatus according to claim 1, wherein the paper type identifier device further comprises: a light irradiating unit configured to irradiate light to a plane of a paper bundle inserted into the recessed portion; a leak light detecting unit configured to receive the irradiated light transmitting the paper bundle and leaking from among the recording paper at an end face of the paper bundle; and a paper type identifying unit configured to identify a type of paper of the inserted paper bundle from an electrical signal obtained from light intensity of the leak light.
 3. The image forming apparatus according to claim 2, wherein the leak light detecting unit receives leak light in a thickness direction of a paper bundle irradiated by the light irradiating unit and converts the light to an electrical signal to obtain a leak light curve.
 4. The image forming apparatus according to claim 3, wherein the paper type identifying unit identifies a paper type from the leak light curve obtained at the leak light detecting unit.
 5. The image forming apparatus according to claim 3, wherein the paper type identifying unit measures an inter-peak distance of the leak light curve, senses thickness of the recording paper, and identifies a paper type.
 6. The image forming apparatus according to claim 3, wherein the paper type identifying unit integrates a signal that corresponds to leak light in a direction substantially perpendicular to the thickness direction of the paper bundle to obtain an integral leak light curve in the thickness direction of the paper bundle.
 7. The image forming apparatus according to claim 5, wherein the paper type identifying unit identifies a paper type from the leak light curve obtained at the leak light detecting unit.
 8. The image forming apparatus according to claim 6, wherein the paper type identifying unit measures an inter-peak distance of the leak light integral curve, senses thickness of the recording paper, and identifies a paper type.
 9. An image forming apparatus comprising the paper type identifier device according to claim 1, the device further comprising: a paper bundle insertion sensing unit configured to sense insertion of the paper bundle inserted into the recessed portion; a light irradiating unit configured to irradiate light onto one face of the paper bundle when insertion of the paper bundle is sensed by the paper bundle insertion sensing unit; a leak light detecting unit configured to detect light intensity leaking from among the recording paper in a thickness direction of the paper bundle, of light irradiated to one face of the paper bundle by the light irradiating unit, and converting the detected light to an electrical signal to obtain a leak light curve; an integrating unit configured to integrate the electrical signal obtained by the leak light detecting unit in a direction substantially perpendicular to the thickness direction of the paper bundle to obtain an integral light curve; an inter-peak distance detecting unit configured to measure an inter-peak distance between adjacent local maximum values or local minimum values, from the integral leak light curve obtained by the integrating unit; and a paper type identifying unit configured to identify a paper type of the paper bundle from the inter-peak distance obtained by the inter-peak distance detecting unit.
 10. The image forming apparatus according to claim 9, wherein the leakage light detecting unit is a two-dimensional image sensor configured to receive the leak light.
 11. The image forming apparatus according to claim 10, wherein the paper bundle insertion sensing unit includes a sensing light source and a light receiving device configured to receive light emitted from the sensing light source which are provided in opposite in the recessed portion, and senses insertion of the paper bundle by interrupting light emitted from the sensing light source and received by the light receiving device.
 12. An image forming apparatus comprising the paper type identifier device according to claim 1, the device further comprising: a paper bundle insertion sensing unit configured to sense insertion of the paper bundle inserted into the recessed portion; a light irradiating unit configured to irradiate light onto one face of the paper bundle when insertion of the paper bundle is sensed by the paper bundle insertion sensing unit; a leak light detecting unit configured to detect light intensity leaking from among the recording paper in a thickness direction of the paper bundle, of light irradiated to one face of the paper bundle by the light irradiating unit, and converting the detected light to an electrical signal to obtain a leak light curve; an optical lens that is provided on a light receiving face of the leak light detecting unit and that focuses leak light in a direction substantially perpendicular to thickness of the paper bundle; an inter-peak distance detection unit configured to measure an inter-peak distance between adjacent local maximum values or local minimum values from a curve obtained by integrating the leak light obtained by the optical lens; and a paper type identifying unit configured to identify a paper type of the paper bundle from the inter-peak distance obtained by the inter-peak distance detecting unit.
 13. The image forming apparatus according to claim 12, wherein the optical lens is a cylindrical lens.
 14. The image forming apparatus according to claim 1, wherein the type of the recording paper is fed back to the image generating unit.
 15. A paper type identifying method of an image forming apparatus which comprises: an image generating unit configured to generate an image to be printed onto recording paper; a paper type specifying unit for a user to specify that a type of the recording paper is directly identified or that a type of the recording paper is automatically identified; a paper type identifier device configured to automatically identify a type of the recording paper when automatically identifying a type of the recording paper is specified by the paper type specifying unit; and a printing unit configured to print on the recording paper the image generated by the image generating unit according to a type of the recording paper identified by the paper type identifier device, the method comprising: irradiating light to one face of the paper bundle, receiving light leaking from an end face of the paper bundle, and identifying a type of the recording paper when the paper bundle made of a plurality of the recording paper is inserted into a recessed portion provided on an external face of the image forming apparatus.
 16. A paper type identifying method of an image forming apparatus which comprises: an image generating unit configured to generate an image to be printed onto recording paper; a paper type specifying unit for a user to specify that a type of the recording paper is directly identified or that a type of the recording paper is automatically identified; a paper type identifier device configured to automatically identify a type of the recording paper when automatically identifying a type of the recording paper is specified by the paper type specifying unit; and a printing unit configured to print on the recording paper the image generated by the image generating unit according to a type of the recording paper identified by the paper type identifier device, the method comprising: irradiating light to one face of the paper bundle and receiving light leaking from an end face of the paper bundle when the paper bundle made of a plurality of the recording paper is inserted into a recessed portion provided on an external face of the image forming apparatus; obtaining a leak light curve in a thickness direction of the paper bundle and detecting an inter-peak distance from the curve; obtaining thickness of the recording paper from the inter-peak distance; and identifying a type of the recording paper from thickness of the recording paper.
 17. A paper type identifying method of an image forming apparatus which comprises: an image generating unit configured to generate an image to be printed onto recording paper; a paper type specifying unit for a user to specify that a type of the recording paper is directly identified or that a type of the recording paper is automatically identified; a paper type identifier device configured to automatically identify a type of the recording paper when automatically identifying a type of the recording paper is specified by the paper type specifying unit; and a printing unit configured to print on the recording paper the image generated by the image generating unit according to a type of the recording paper identified by the paper type identifier device, the method comprising: irradiating light to one face of the paper bundle when insertion of the paper bundle inserted into the recessed portion provided on an external face of the image forming apparatus is sensed; detecting light intensity leaking from among the recording paper in the thickness direction of the paper bundle, of light irradiated to one face of the paper bundle, and converting the detected light to an electrical signal; obtaining an integral leak light curve by integrating the converted electrical signal in a direction substantially perpendicular to the thickness direction of the paper bundle; detecting an inter-peak distance between adjacent local maximum values or local minimum values from the obtained integral leak light curve; and identifying a paper type of the paper bundle from the detected inter-peak distance.
 18. An image forming apparatus comprising: a latent image generating unit configured to generate a latent image to be printed on recording paper; a paper type specifying unit configured to for a user to specify that a type of the recording paper is directly identified or that a type of the recording paper is automatically identified; and a paper type identifier device having a recessed portion on an external face of the image forming apparatus, the identifier device being operable to identify a type of the recording paper from a paper bundle made of a plurality of paper, inserted into the recessed portion by the user when automatically identifying a type of the recording paper is specified by the paper type specifying unit; and a printing unit configured to print on the printing paper the latent image generated by the latent image generating unit, based on a printing condition according to a type of the recording paper identified by the paper type identifier device.
 19. The image forming apparatus according to claim 18, wherein the printing condition is a developing voltage configured to develop the latent image.
 20. The image forming apparatus according to claim 18, wherein the printing condition is a transfer bias voltage configured to transfer to the recording paper after the latent image is developed.
 21. The image forming apparatus according to claim 18, wherein the printing condition is a fixing temperature at which the transferred image is fixed to the printing paper after the latent image is developed, and the developed image is transferred to the recording paper. 